(1) Field of the Invention
This invention relates to planting agricultural crops, and more particularly to attaching the planting units of a drill. (111/85)
(2) Description of the Prior Art
Almost all planters or drills will have an opening device to form a furrow A seed chute will provide means for dropping seed into the furrow. Then, the furrow will be closed, covering the seed with earth. Some will have additional implements. E.g., SCOTT, U.S. Pat. No. 4,432,292 also shows a gauge wheel to regulate the depth of the furrow device; an earth working implement to remove dry dirt from the top of the soil, and a press wheel to press the drilled seed into firm soil. The covering device is in the form of a drag which not only closes the furrow and covers the seed, but also, cultivates the soil which is used to cover the planted seed.
Before this application was filed, the applicant caused a search to be made in the U.S. Patent and Trademark Office.
The following patents were found on that search:
______________________________________ HENDRIX ET AL. 4,267,783 FRASE ET AL. 4,398,478 ROBINSON, JR. ET AL 4,423,788 LIENEMANN ET AL. 4,425,857 ______________________________________
It may be seen that all of these patents show it is old to use a parallel linkage mechanism with planters. Three of them show that it is old to use the parallel linkage mechanism with drills wherein a single planter seed box is used to feed a plurality of planting units. Also, these three (those to International Harvester Co.: namely, FRASE ET AL., ROBINSON, JR. ET AL., and LIENEMANN ET AL.) show that it is old to use a spring within the parallel motion linkage to bias the planting units so that additional forces are exerted on the planting units.
HENDRIX ET AL. and SCOTT show a unit wherein there is a separate seed box for each planting unit. Also these patents appear to disclose a tool bar which is capable of being rotated about its longitudinal axis.
Applicant is aware of an advertizing flier for DewEze Super Drill 40, manufactured by DEWEZE Mfg., Inc., East Highway 160, Harper, Kans. 67058. These units have a width of about 40 feet with over 30 planting units supported by parallel motion linkage. Applicant understands that these units are designed to have the tool bar rotate about its longitudinal axis so that the planting units might have the proper angular orientation to the land being planted.
One of the principle attributes of the parallel linkage planting system is to provide accurate and uniform depth of seed placement in varying soil and topographical conditions. Parallel link openers have long been used commercially on planters where there are just a few of the units to be adjusted. However, parallel link openers have lacked wide spread commercial acceptance on drills because of the large number of individual planting units found on drills and the corresponding difficulty in making adjustments on all of these units.